Sharing information on Weeds -

"What is a weed?" Emerson wrote. "A plant whose virtues have not yet been discovered."

Children have been taught in the garden that a weed is any plant that is not intended to be part of the garden. In other words a rose bush could be a weed if it is in a vegetable garden! These sites will help us identify the weeds that need to be removed from our butterfly and vegetable gardens....Many plants are considered invasive, check out this site to learn about those.
http://www.invasive.org/gist/methods.html

Nashville's Least Wanted

These plants may seem to have no redeeming virtues, but since we can't get rid of them, we should use them in the curriculum.
See below for general ways to use them.

Photo	Name	Comments	Uses in the Curriculum
	Johnson Grass		This is a good example of a plant which uses underground runners to reproduce
	Bermuda Grass (and other "Crab" Grass)		These plants use both underground and above ground runners. They are unstoppable! Eradicating them in your garden if the garden is surrounded by Bermuda is next to impossible --- the best strategy ispulling as much as you can and then covering with cardboard (to cut out all light) and mulch over that!
	NutWeed		Nut Weed uses small tubers, which break off when you pull the plant up. Some people call the tubers "nuts" which you must extracate from the ground to be rid of the grass. This plant is a member of the papyrus family.
	Horse Nettle	This is a relative of tomatoes. It is thorny.	Horse nettles reproduce by seeds, and defeat gardeners with seed banking. I have prevented these nettles from flowering for three years, but each year new plants come up. Some of its seeds germinate after 1 winter, but some stay dormant much longer.
	Field Bind Weed	This can completely cover our raspberries
	Poke	The berries look edible but are poisonous as are all other parts of the plant.	Poke berries were used to make ink in the 18th century. Several source suggest that the Declaration of Independence was written with fermented pokeberry ink. Because of the toxic nature of this plant be sure to wear gloves. The fermentation process changes the color and makes the ink permanent. It could be used in a demonstration of colonial life. I haven't tried it yet, but I have a bottle of homemade ink and a bag of turkey feathers. Here is a link to a recipe http://www.greatstems.com/2010/11/history-lesson-part-ii----pokeweed-ink.html

Invasive Wild Plants with Redeeming Virtues

Photo	Name	Redeeming Virtue	Use in the Curriculum
	Plantain	This is the favorite food of the caterpillar of Buckeye butter- flies. Also the seed heads are fun to shoot.	We want to have breeding colonies for our butterflies. While butterflies are generalists, caterpillars specialize.This is an important fact to understand about butterflies. We let a few plantains grow in beds to save the caterpillars from the mowers Plaintain is also used herbally --- check it out http://www.prairielandherbs.com/plantain.htm
	Lambs Quarters, aka Goose Foot Spinach	The leaves are delicious	We harvest them early in the season, and leave a few for the fall. They can be used in a unit on the hunter-gatherer life style. Pioneers ate this "weed" in salads and as a cooked green. You can substitute it for spinach!
	Dandelion	They produce flowers early and so are very good for bees. Their deep roots bring up minerals which other plants can use.	They are a good example of a weed which survives by having a deep root. Their seeds are a good example of seeds distributed by the wind. They were not always a weed. They probably came to America on the Mayflower! For centuries they have been appreciated for their many values -- see http://www.mofga.org/Default.aspx?tabid=756 for an alternative veiw of them. Here is a great for teaching about invasive species.
	Common Buttercup (Ranunculus acris)	We don't pull these at all. We use them to make pressed flowers	This is a good example of the importance of scientific names. The common name "buttercup" refers to this little flower in the North, but to a daffodil in the south. The scientific name is universal. The genus name Ranunculus tells us what other plants are closely related (mostly other buttercups). The species name acris tells us that it is not good to eat. In fact most Ranunculi are poisonous.
	Violet	We control our violets but leave a lot for pressed flowers. They are also edible.	I have students compare wild violets with pansies to illustrate selective breeding and natural selection. The two are members of the same genus (Viola)

Using Weeds in the Curriculum

Teaching Co-evolution

My mother used to say that it was easy to tell a plant from a weed. "Pull it up and if it grows back, it was a weed." What makes weeds so tough? My mother had a saying which she repeated whenever she wanted to tell me that I was tough! "Weeds don't die easy." she would say.

When we try to get rid of weeds we impose a selective bias. Let us say we are pulling up dandelions. Some have fairly deep roots, while others have very deep roots. We can get out the first but not the second. The next generation of dandelions will have longer roots, because the long rooted ones survive to reproduce. Looking at the weeds listed above we can see how in each case our attempts to get rid of them selects for the weeds most resistant to pulling.

The influence of one species on the evolution of another is called co-evolution and it occurs everywhere. It is important that students understand the concept.

Involving Students in Weeding

At Park Avenue, we include students in clearing beds for spring planting but not in later weeding. I would be interested in hearing about the experience of other schools

Here are some helpful sites for further information.

Broadleaf Weed Gallery This is a gallery of photos of common broadleaf weeds .